I would like to add a facet to a search_api view filtering on the content "changed" field. I would like to use friendly naming like "This week", "This month" etc.
There is an [answer here][1] stating that custom code is needed. However this answer is for Drupal 6 (about 8 years old) and refers to a date range  field while "changed" is a timestamp. 

Currently if I add Date processor capability to this facet I have a granularity option. If I select a month granularity I get a basic "time ago" feature but seem to get very odd results. 

EG. Clicking on "3 months ago (3)" in the below list gives me 13 items.
The url generated is `&facets_query=&keyword[0]=last_updated:2021-05-22` (As of today July 22)


    Last updated
    3 months ago (3)
    6 months ago (3)
    7 months ago (2)
    8 months ago (9)
    10 months ago (1)
    11 months ago (6)
    1 year 0 months ago (7)

Questions: 

 1. Is there an updated answer available for creating a friendly set of date ranges?
 2. Why could I be I getting these incorrect facet counts?


  [1]: https://drupal.stackexchange.com/questions/41781/apachesolr-search-results-facet-filter-by-date-range